Leinster flanker Kevin McLaughlin will complete a spectacular rise to the top when he makes his Ireland debut on Saturday - just a year after almost turning his back on the game.

The 25-year-old blindside, who had made just four starts for his province before this season, will start against Italy at Croke Park after Ulster's Stephen Ferris failed to recover from a knee injury that also threatens his participation in the showdown with Franceon February 13.

Ravaged by injury and a succession of operations - one knee and two shoulder - McLaughlin's commitment to the sport was on the wane last season and after a warning from Leinster coach Michael Cheika that his future was in doubt he began to explore options outside rugby. A lack of fitness and the outstanding form of Australian flanker Rocky Elsom had limited his chances until that point and he was forced to look on as Leinster claimed the Heineken Cup crown. But Elsom's decision to return home opened the door once again and with his own body holding together, McLaughlin seized the chance to make an unlikely ascent into the Test arena.

"Last season was tough for me. With Rocky there I wasn't getting any game time," said the choir singer. "I had to assess what was happening. I wasn't helped by the constant injuries. I had a couple of years where I struggled to make a breakthrough but that's just allowed me to appreciate this season all the more.

"I've come through it and am delighted to be seeing some reward. Last season I was looking at careers other than rugby. I definitely had second thoughts. I was asking myself if I was up to it physically. Was I ever going to make the breakthrough?

"When you get to the age of 24-25 it's time to start to playing games regularly, so I definitely had doubts and am delighted to have stuck with it. The coaching staff at Leinster have been good to me and kept faith. I did OK in September but they realised I could get better so kept playing me week in, week out.

"Luckily I repaid them by improving. Now I have my chance in the Irish set-up. It's time to repay some of the faith shown in me."

Elsom's departure left a gaping hole in Leinster's back row, yet according to Ireland captain Brian O'Driscoll, McLaughlin has proved a worthy successor.

"Kevin has been very consistent. He's been a big impact player for us, has carried well and has a high work rate," said the Leinster centre. "He does the simple things you ask of your blindside flanker. People were waxing lyrical about Rocky last year and he was great for us. People wanted to know how we were going to replace him. Well I think Kevin has done a fairly good job of that and the change has been fairly seamless."

Ireland open their Grand Slam defence with Ronan O'Gara at fly-half after Jonathan Sexton was ruled out with a dead leg. Kidney hopes to have a better idea over the next 72 hours of Sexton's availability for France on Saturday week.

The promotion of McLaughlin and selection of O'Gara, who was usurped by rising star Sexton last autumn, overshadowed the return of Andrew Trimble and Gordon D'Arcy. Trimble starts on the left wing after impressing for Ulster this season while the in-form D'Arcy edges Paddy Wallace at inside centre.